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232 IGUANA  •  VOLUME 13, NUMBER 3  •  SEPTEMBER 2006 CONSERVATION RESEARCH REPORTS

Reproductive Investment 
of a Lacertid Lizard in 
Fragmented Habitat

DÍAZ ET AL. (2005. Conservation Biology
19:1571–1577) studied the effect of
habitat fragmentation on female repro-
ductive investment in a widely distrib-
uted lacertid lizard (Psammodromus
algirus) in a mixed-forest archipelago of
deciduous and evergreen oak woods in
northern Spain. They captured gravid
females in fragments (≤ 10 ha) and
forests (≥ 200 ha) and brought them to
the laboratory, where they laid eggs. Eggs
were incubated and the first cohort of
juveniles released into the wild in order
to monitor survival. Females from frag-
ments produced a smaller clutch mass
and laid fewer eggs (relative to mean egg
mass) than females of similar body size
from forests. Lizards did not trade larger
clutches for larger offspring, however,
because females from fragments did not
lay larger eggs (relative to their number)
than females from forests. Among the
first cohort of juveniles, larger egg mass
and body size increased the probability of
recapture the next year. Thus, fragmenta-
tion decreased the relative fecundity of
lizards without increasing the quality of
their offspring. Reduced energy availabil-
ity, increased predation risk, and demo-
graphic stochasticity could decrease the
fitness of lizards in fragmented habitats,
which could contribute to the regional
scarcity of this species in agricultural
areas sprinkled with small patches of oth-

erwise suitable forest. Results demon-
strated that predictable reduction of
reproductive output with decreasing size
of habitat patches can be added to the
already known processes that cause
inverse density dependence at low popu-
lation numbers.

The Conservation of Brazilian
Reptiles: Challenges for a

Megadiverse Country
About 650 species — 330 snakes, 230
lizards, 50 amphisbaenids, 6 caimans,
and 35 turtles — comprise the known
reptilian fauna of Brazil. Only 20 species
are considered threatened. Except for the
marine and freshwater turtles, which suf-
fer from overexploitation and habitat
destruction, species are threatened
because of rarity and extremely restricted
ranges. Despite its richness and diversity,
research on Brazil’s reptilian fauna
remains largely restricted to alpha taxon-
omy. TREFAUT RODRIGUES (2005.
Conservation Biology 19:659–664) sug-
gested that surveys, an electronic data-
base of all herpetological collections, and
phylogeographic studies based on molec-
ular genetic techniques are needed to
improve our understanding of the bio-
geography of Brazilian reptiles and to
delineate effective conservation strategies
to preserve the evolutionary potential of
existing lineages. Autecological, popula-
tion, and community studies that moni-
tor effects of habitat degradation, frag-

mentation and loss, pollution, and
exploitation are needed for a better
understanding of the effects of the wide-
spread and ever-worsening degradation
of Brazil’s natural ecosystems.

Effect of Vegetation Matrix 
on Animal Dispersal: 

Genetic Evidence from a Study 
of Endangered Skinks

Maintaining connectivity in fragmented
landscapes is a key principle of biological
conservation. Although corridors are a
widely accepted approach to connecting
populations, their merits are still debated,
and they may be impractical in many sit-
uations. A focus on management of the
vegetation matrix between populations
has been advocated as an alternative way
to deal with habitat fragmentation and
has theoretical support. BERRY ET AL.
(2005. Conservation Biology 19:855–864)
combined microsatellite DNA and
demographic data to provide an empiri-
cal account of how two forms of agricul-
tural land use affect the connectivity of
insular populations of an endangered
skink in southern New Zealand. The
Grand Skink (Oligosoma grande) lives in
small populations (approximately 20
individuals) on rock outcrops separated
from one another by 50–150 m of inhos-
pitable matrix vegetation (either native
tussock grassland or exotic pasture).
Skinks typically dispersed short distances,
and the nature of the matrix both quan-
titatively and qualitatively affected disper-
sal dynamics. Skink populations in pas-
ture were significantly more genetically
structured and had less genetic variation
than similar populations in tussock,

C O N S E R V A T I O N  R E S E A R C H  R E P O R T S

The reproductive output of lizards (Psammodromus algirus) from fragmented habitat patches was
reduced when compared to lizards from forests.

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The Black Caiman (Melanosuchus niger) is a
threatened species, but the conservation sta-
tus of many of Brazil’s other reptilian species
is uncertain, a condition largely attributable
to a paucity of information.

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IGUANA  •  VOLUME 13, NUMBER 3  •  SEPTEMBER 2006 233CONSERVATION RESEARCH REPORTS

implying less dispersal between popula-
tions in pasture than tussock.
Furthermore, although female-biased dis-
persal was a feature of populations in tus-
sock, no sex bias was evident in pasture.
In addition, Bayesian individual-based
genetic assignment tests that incorpo-
rated prior mark-recapture information
revealed that some populations produced
many emigrants but received few immi-
grants, whereas other populations were
relatively insular. Patterns of dispersal and
response to matrix vegetation were com-
plex, and the causes of these patterns
deserve attention in future studies of
habitat fragmentation. Managing the
vegetation matrix may be a practical way
to connect animal populations in some
situations.

Disruption of a Plant-Lizard 
Seed Dispersal System and Its Effects

on a Threatened Endemic Plant
The introduction of exotic species to an
island can have significant effects on the
population density and distribution of
native species and on the ecological and
evolutionary interactions among them
(e.g., plant-animal mutualisms). The dis-
ruption of these interactions can be dra-
matic, significantly reducing the repro-
ductive success of the species and even
leading to their extinction. On Menorca
Island (Balearic Islands, western
Mediterranean), TRAVESET AND RIERA

(2005. Conservation Biology 19:421–
431) examined the consequences of the
disruption of the mutualism between
two endemic species: a perennial shrub
(Daphne rodriguezii) and a frugivorous
lizard (Podarcis lilfordi). The lizard
became extinct from this island (as well
as from Mallorca) as a result of the intro-

duction of carnivorous mammals, which
has continued since Roman times. The
relict mutualism between D. rodriguezii
and the lizard currently persists only in
an islet (60 ha) where P. lilfordi remains
abundant. The authors hypothesized that
the absence of this lizard from most
Menorcan populations is the factor caus-
ing the regression of this plant, currently
considered at risk of extinction. Through
observation and experimentation in the
field and laboratory, they found strong
evidence that a lack of seed dispersal in
Menorca is the main cause of the low
seedling recruitment. First, the popula-
tion with greatest seedling recruitment
was that in the islet where lizards were
abundant. Second, lizards appeared to be
the only dispersers of D. rodriguezii.
Lizards consumed large amounts of
fruits, without affecting either germina-
tion or seedling growth, and moved seeds
to sites suitable for plant establishment.
Seedlings in Menorca, in contrast,
recruited almost exclusively under the
parent plants. Third, the effect of other
factors that may influence plant popula-
tion growth (a low fruit set and a high
postdispersal seed predation) was similar
between the islet and the Menorcan pop-
ulations. These appear to be the first
results to quantitatively show that a bio-
logical invasion can cause a disruption of
a specialized plant-vertebrate mutualism
that sets the plant partner on the road to
extinction.

Predicting the Impact of 
Sea-Level Rise on Caribbean 
Sea Turtle Nesting Habitat

The projected rise in sea level is likely to
increase the vulnerability of coastal zones
in the Caribbean, which are already under
pressure from a combination of anthro-
pogenic activities and natural processes.
One of the major effects will be a loss of
beach habitat, which provides nesting
sites for endangered sea turtles. To assess
the potential impacts of sea-level rise on
sea turtle nesting habitat, FISH ET AL.
(2005. Conservation Biology 19:482–491)
used beach profile measurements of tur-
tle nesting beaches on Bonaire,
Netherlands Antilles, to develop elevation
models of individual beaches in a geo-
graphic information system. These mod-

The lack of seed dispersal by a lizard (Podarcis lilfordi) extinct on Menorca (a Balearic island in
the western Mediterranean) may be responsible for the decline in populations of a perennial
shrub considered at risk of extinction.

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The Grand Skink (Oligosoma grande) of New
Zealand lives in small populations of approx-
imately 20 individuals on rock outcrops sep-
arated from one another by 50–150 m of
inhospitable vegetation.

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Hawksbill Turtles (Eretmochelys imbricata)
often nest in dense beach vegetation. Their
nesting beaches as well as those of other
Caribbean sea turtles could be threatened by
rising sea levels. Photograph courtesy of the
Nature Foundation of St. Maarten (NAF-
SXM).

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234 IGUANA  •  VOLUME 13, NUMBER 3  •  SEPTEMBER 2006 CONSERVATION RESEARCH REPORTS

els were then used to quantify areas of
beach vulnerable to three different scenar-
ios of a rise in sea level. Physical charac-
teristics of the beaches were also recorded
and related to beach vulnerability, flood-
ing, and nesting frequency. Beaches var-
ied in physical characteristics and there-
fore in their vulnerability to flooding. Up
to 32% of the total current beach area
could be lost with a 0.5-m rise in sea level,
with lower, narrower beaches being the
most vulnerable. Vulnerability varied with
land use adjacent to the beach. These pre-
dictions about loss of nesting habitat have
important implications for turtle popula-
tions in the region. 

Burn Regimes and 
Tallgrass Prairie Reptiles

The Flint Hills region of Kansas is the
largest contiguous area of tallgrass prairie
remaining today. Historically, the tallgrass
prairie burned every 2–3 yr on average,
but current land managers have altered
burn regimes, resulting in a range of habi-
tats from annually burned to long-term
unburned. WILGERS AND HORNE (2006.
Journal of Herpetology 40:73–84) used
drift fence/funnel trap arrays and cover-
boards to estimate species richness, even-
ness, and diversity of herpetofauna within
three different burn regimes: annual, 4-yr,
and long-term unburned at Konza Prairie
Biological Station, Riley County, Kansas.
During the spring and fall of 2003–2004,

315 individuals from 20 species were cap-
tured across all burn regimes.
Herpetofaunal species richness, evenness,
and diversity estimates were not different
between the three burn treatments.
However, because of species-specific
responses to individual burn regimes,
community composition was significantly
different between the habitats. Four
species exhibited preferences among burn
regimes, which differed significantly from
independent assortment, with Great
Plains Skinks (Eumeces obsoletus) and
Texas Horned Lizards (Phrynosoma cornu-
tum) preferring annual burn treatments,
Ground Skinks (Scincella lateralis) prefer-
ring 4-yr burn treatments, and Ringneck
Snakes (Diadophis punctatus) preferring
longterm unburned treatments. Species-
specific responses were likely because of
changes in vegetation structure and
microhabitat (temperature and moisture
content) created through different fre-
quencies of fire disturbances. Maximizing
large-scale herpetofaunal diversity across
the Flint Hills’ rangelands could be
accomplished by creating a large number
of small-scale habitat types through a
mosaic style burning plan. 

Alligator Snapping Turtles in
Southeastern Louisiana,

BOUNDY AND KENNEDY (2006. Chelonian
Conservation and Biology 5:3–9) trapped
200 Alligator Snapping Turtles

(Macrochelys temminckii) at an average
rate of 0.057 turtles per trap-night in all
but 1 of 33 sites in southeastern
Louisiana. Trap rate varied between sites,
by harvest pressure levels at sites, and by
season, but not by hydrology. Perceived
trap rate differences under different har-
vest regimes appeared to be a function of
seasonal differences in trap rate. No dif-
ferences in sex ratio or percentage of
immature turtles were detected between
sites, harvest regimes, seasons, or water-
body types. Turtle weight varied between
harvest regimes and hydrology.
Weight–length relations for turtles was
highly correlated and similar between
sexes, except that males continued to
grow to larger sizes than females (males
averaged 150% female weight and 118%
female carapace length). Sex ratio was
1:1, and immature turtles made up 48%
of the total. Average sizes of turtles were
very similar between Louisiana and tur-
tles from surveys in several other states.
Population structure differed between
surveys, with Louisiana having a higher
percentage of immature turtles and lower
trap rate than elsewhere. Population dif-
ferences could not entirely be explained
by differences in harvest regimes between
states. Large-scale turtle butchering oper-
ations in southern Louisiana have closed,
as has commercial harvest. Anecdotal
reports that Alligator Snappers were
nearly extirpated from a heavily harvested
site proved erroneous. The authors rec-
ommended resurvey of sites to determine
current population trends.

Great Plains Skinks (Eumeces obsoletus) were among four species of tallgrass prairie-dwelling rep-
tiles that demonstrated a clear preference for a particular burn regime, favoring annual burn
treatments. 

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Louisiana populations of Alligator Snapping
Turtles (Macrochelys temminckii) included
more immature turtles and exhibited a lower
trap rate than populations surveyed in other
southern states.

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